Digital projectors, also known as digital projection display systems, are a specialized form of computer display that projects an enlarged image on a target object (e.g. movie screen, etc.). Such devices are commonly used in presentations. While there are numerous types of digital projection display systems, two main types are in use today.
Older, less expensive digital projection display systems typically employ three transparent (LCD) panels, one for each of the primary colors (e.g. red, green, and blue). The light transmittivity of each pixel varies depending on the image data received from a computer. In use, light from a lamp is directed through the LCD panels, collimated using a lens, and projected onto a screen.
A newer, more expensive technology is known as digital light processing (DLP) and involves tiny mirrors that are used instead of transparent panels. Typically each mirror represents one pixel, and the light, rather than passing through a panel, is reflected from the mirror. In operation, the mirrors move back and forth, varying the amount of light that reaches the projection lens from each pixel. Color may obtained by passing the light from the lamp through a rotating wheel with red, green, and blue filters. This subjects the mirrors to light at each of the primary colors in a rapid rotating sequence. To this end, a color-modulated image is projected that the human eye sees as natural color.
To date, these and other types of projectors have typically been used for projecting images onto two-dimensional objects such as a screen, etc. While there has been some research involving the projection of images onto three-dimensional objects, such work has been limited.